More HVAC decisions and questions.

[CMcAllister]

Well, we've decided to not go with radiant floor heat for a number of reasons, including budget. Now we need to decide what we are going to use.

This is for a 40x52x12 pole building in southern PA, well insulated, worked in everyday and all day, and will also be air conditioned. I've had heat pumps, overhead radiant tube heaters,and forced hot air recommended with a variety of energy sources. At this point, I don't know what we are going to use, so I'm asking for suggestions for high efficiency, comfort and reliability HVAC options. What would you use and why?

Also, we are insulating the ceiling and walls, but would it be worth installing insulation under the concrete, even though we are not using in-floor radiant? Any experience or information on the benefits (or lack of) using insulation under the floor?

Thanks.

 

[stingry]

Will this be one large space or will it be divided into smaller spaces?

 

[CMcAllister]

One large space, May have a small half bath/utility room, storage room, clean/assembly room, but mostly an open work area.

 

[brewchief]

I would not hesitate to insulate under the concrete, my personal experience with a friends building tells me it's well worth it. If you want A/C you will need some sort of duct system, no sense in using tube heaters if you are also putting in ductwork IMHO.

What type of work is being done in the space? If it's commercial you may be required by code to bring in a certain amount of fresh air.

What fuel sources are available?

How much room is there for ductwork? Can it be exposed below the ceiling or does it need to go in the attic?

 

[CMcAllister]

Natural gas is not available at my site. Electric or gas are the two real options. We are definitely going to install A/C. The shop will be used for auto restoration, race car work, metal work and general metal fabrication. Also, as a general workshop. No spray painting. Don't think commercial codes will be an issue. Duct work can go under or above the ceiling. Obviously it would look better if it was above.

I expect to spend a lot of time in this building. Initial cost is an issue because of our budget for this project. Long term operating cost is more important.

Total cost of electric was about 10 cents/KWH on our last bill, if that helps with your recommendations.

Thanks.

 

[BadgerBoilerMN]

First, a proper heating/cooling load should be performed by a professional. This should include advice on ventilation. A heat recovery ventilator is a must.

The slab must be insulated and radiant floor would be the preferred method but for a tight budget a sealed combustion air to air propane furnace with exposed duct work will give you good heating and cooling efficiency if properly sized.

Contractors who don't or won't do the heat loads should not be considered. Naturally, this is not a DIY project.

Starting with available fuels and the cost per million btu will give you the information for comparison. Some power companies will discount off-peak and like programs.

 

[BadgerBoilerMN]

Impossible! Give up now!

Or have a real heat load done. Residential equipment will be more than adeqate for most garages such az yours. For comfort it is radiant doors, infrared and forced air. I do not consider unit heaters for occupied spaces.

I use off-peak electric boiler and wood with a minisplit for a.c. to protect tools.

The standard for forced air is airtight duct work so cellulose@ R50 is more than adequate for duct work in above the ceiling.